Choosing an ISP to Support SD-WAN

Choosing an ISP to Support SD-WAN

You’re preparing for conversion to software-defined wide area networking (SD-WAN), and there are good reasons to do so. You can expect to benefit from the convenience of centralized management and visibility, the cost savings of a subscription-based payment model, scalability and network traffic prioritization. As cloud spending increases and the Internet of Things (IoT) grows, more enterprises are likely to make the switch to SD-WAN.

What many teams miss in their transition to SD-WAN is the support the Internet infrastructure provides. Many IT teams think of Internet connectivity as simply a commodity and don’t consider the quality of their Internet service provider (ISP). One of the challenges is that ISPs have no formal service level agreements (SLAs). When you use an ISP, you assume that the right level of quality and connectivity is there.

When you are connected through a broadband line, like a Digital Subscriber Line (DSL) or cable, your choice of ISP is limited. When you’re using a direct access line to the Internet, you have more choices. While there’s a lot you may not be able to tell about the provider, you can look into the nature of the connection to evaluate if it’s right for SD-WAN.

What you should be looking for: Tier 1 backbones. There are two main ways that local ISPs connect to the broader Internet. They may connect to global backbones, or they may use local peering points. Peering points tend to be oversubscribed, with many running at only 60 to 70% of capacity. During peak period, there can be rampant packet drops and retransmission. Even if your local ISP line isn’t oversubscribed, there are generally multiple router hops to land at the peering point. The more hops in the connection, the worse the performance of the connection.

When evaluating a local ISP for SD-WAN, look at the ISP’s access to the Internet. Choose one that has a tier-1 backbone. What this means is that the ISP is connected directly to the network of other global tier-1 backbones. This minimizes the likelihood of packets being dropped before they reach their destination.

It’s important to note that there’s no tier-1 backbone certification that your ISP will be able to advertise; you may have to ask how they connect to the global Internet. One way to verify that your provider is a tier-1 backbone ISP is to find out the number of Autonomous Systems, which reflects a single network. The higher the AS count, the more direct connections the ISP has.

At Wanify, we help you through each step of your SD-WAN conversion, including evaluating ISP needs. Contact us for more information about SD-WAN.